Abstract

Interactions between a ferromagnet, cobalt, and a ferroelectric copolymer, poly(vinylidene fluoride with trifluoroethylene) in thin film heterostructures result in a 5% change in the ferroelectricpolarization on application of a perpendicular 6 kG magnetic field corresponding to a magnetoelectric coupling coefficient of . The effect disappears on magnetic saturation, ruling out conventional strain coupling. A simple model posits that the ferroelectricfilm develops in-plane strain gradients, a consequence of the coupling to strain gradients present at the domain walls in the multidomain Co layer, resulting in the measured polarization change via the flexoelectriceffect.